1. Field of the Invention
The present invention relates to remote network management. More specifically, the present invention relates to a method and apparatus for managing network equipment remotely through an Ethernet connection.
2. Related Art
Because of the rapid proliferation of the Internet and multimedia applications, such as video on demand, modern commercial and residential customers are demanding more communication bandwidth and connectivity. This increasing demand is evident in both variable-bit-rate communications (e.g., data services) and fixed-bit-rate communications (e.g., voice services). Customers typically depend upon local-area-networks (LANs) to provide the connectivity necessary to accommodate a growing number of data applications. Meanwhile, a separate network (e.g., a telephone network) provides services for applications that require higher quality of service (QoS). As the volume of network traffic increases and better network technologies emerge, however, it becomes desirable to merge the two separate networks into one integrated and cost-effective high-speed network.
Among the high-speed LAN technologies available today, Fast Ethernet (100BASE Ethernet) and Gigabit Ethernet (1000BASE Ethernet) are the leading choices. Both of these technologies build upon the existing ubiquitous Ethernet standards. They employ the same protocol stack and the same frame format. For the majority of network users, this means that they can extend their existing network equipment to provide 100 Mbps or gigabit speed at a reasonable cost, without the need to re-educate their network administrators and users, and without the need to invest in new network protocols and related hardware.
However, conventional Ethernet technologies can only accommodate asynchronous, packet-based traffic without QoS support. Consequently, Ethernet generally only provides services for applications that do not have stringent QoS requirements (e.g., Internet applications). Mission-critical applications, such as voice communications and financial transactions, have higher QoS requirements and are typically carried on time division multiplexing (TDM) networks (e.g., telephone networks). Although it is possible to carry both types of traffic on one TDM network, it is not cost effective to do so, because TDM networks usually have limited bandwidth, and the network utilization for data traffic is not very efficient. It is therefore preferable to accommodate these two types of traffic on a single high-speed network cost-effectively.
Fortunately, one can take advantage of the xB/yB encoding scheme in Ethernet to accommodate TDM. Generally, Ethernet frames are encoded with an xB/yB scheme, whereby an x-bit word from user data is translated into a y-bit word before it is transmitted onto the physical medium (y is typically larger than x, e.g., 4B/5B, 8B/10B, etc.). The reason for using xB/yB encoding is to use extra bits to increase the number of transitions between “1”s and “0”s for clock synchronization and/or to reduce polarization and to achieve DC balance (i.e., to ensure that there are approximately the same number of “1”s and “0”s).
Originally, the xB/yB encoding schemes were designed to provide a robust transmission under less-than-ideal conditions. However, advances in transmission technologies, especially in optical transmission technologies, have relieved the burden on the encoding schemes to mitigate transmission impairments. As a result, one may use the built-in redundancy of xB/yB encoding (i.e., the extra (y-x) bits in each word) to carry additional information. Moreover, since on an Ethernet link data is transported in a synchronized, continuous sequence of y-bit words, it is now possible to carry TDM traffic using the overhead bandwidth. Consequently, by taking advantage of the redundancy built in the xB/yB encoding, one can carry both variable-bit-rate data traffic and TDM traffic on the same Ethernet link.
Generally, variable-bit-rate communication channels and TDM communication channels are terminated at different network devices. For example, Ethernet channels carrying data traffic are terminated at Ethernet switches or gateways. TDM channels carrying voice traffic, on the other hand, are typically terminated at line interface units (LIUs). These different network devices usually require separate control/management mechanisms.
It is desirable to eliminate the need for two separate network control/management mechanisms in an integrated network that accommodates both Ethernet data traffic and TDM traffic. Hence, what is needed is a method and apparatus for managing network equipment remotely over Ethernet connections.